ENVIRONMENTAL PROBLEMS

The environment is an open system that includes human beings and their surroundings and the tight relationship between them. It's formed by water, air and earth and all the living beings in them.

The most important problems are those that affect the natural resources found in these ecosystems:

Water Pollution:

For the last 10 to 20 years rivers, lakes and seas have been the earth's dustbin harbouring all our rubbish. This is one of humanity's biggest and most worrying problems.

The main pollution sources are:

• The polluted waters produced by homes

• 
  The industrially polluted waters produced by the dumping of chemical substances pollute more than those produced by homes.

• Pesticides and other chemicals used in farming get carried away by rain and end up in rivers and lakes polluting them.

These polluted waters have a big negative effect on the living beings that survive thanks to the normally clean lakes, rivers and seas and this causes acuatic animals and plants to die of poisoning. A big problem is the so-called black-tides, produced when petrol is dumped, either accidentally because of a petrol carrier sinking or by the cleansing of the petrol containers in open waters.

Another subject of great importance is the mass-fishing carried out by fishermen who don't care if the fish caught are of adult size or not. This generates big problems because the smaller fish can't get to adult size in order to reproduce themselves and this can cause the extinction of numerous acuatic species.

Air Pollution:

• Climate changes produced by:

• The greenhouse effect produced by polluting gases released into the atmosphere by industries. The CO2 traps the sun's heat in the atmosphere and temperatures go up.

• Holes in the ozone layer that allow harmful UV sun ray's to go through. These rays heat up the atmosphere and cause the poles to melt and are also harmful for human beings giving us skin cancer, vision problems as well as causing problems to plants during photosynthesis.

• Acid rain caused by the harmful gases released into the atmosphere which get absorbed into the clouds and cause the rain to be acidic.

Air pollution is more preocupying in big cities where it hangs over the buildings in a reddish mist called smog. This is produced mainly because of the exhaust fumes released by the numerous cars and industries that are found in cities.

Terrestrial Pollution:

Fires, desertizing and the over-cutting of trees are some of the biggest problems of terrestrial pollution.

Polluting substances such as pesticides, toxic metals an alloys and un-organic compounds that harm not only humans but also animals and plants must also be considered important.

The Environment is negatively afected by pesticides, excesive farming, erosion, the excesive use of water resources thet harm the earth, the using-up of fossil fuels and excessive tree cutting.

Tree cutting is one of the biggest problems because in 8000 years we have lost nearly half of the world's forests (out of 6000 million hectares we have 3500 million left) and each year between 14 and 15 million hectares of forest disappear. The tropical rainforest has been the most harmed because the wood provided by it's trees is not only hard but also very beautiful and in great demnad.

Desertization is produced by excessive farming done by farmers who cut all vegetation and when heavy rain and winds arrive they carry all the earth to the rivers and seas taking with them the basic nutrients that plants use to grow.

Fires usually originated in summer destroy great portions of vegetation.

Inorganic materials left in forests and the countryside such as empty bottles, cans and food containers cause animals to choke on them or harm themselves which can later cause their death.

Because of all these frightening facts about our world's state, many countries are creating special policies regarding the environment and it's preservation so that human evolution doesn't destroy completely the Earth, and to damage it as little as possible.